[Morphogenesis of the Staphylocystis furcata cysticercoid (Cyclophyllidea, Hymenolepididae)].

The morphogenesis of the Staphylocystis furcata (Stieda, 1862) cysticercoids has been studied in the experimentally infected beetles Geotrupes stercorosus and their structural and ontogenetic features have been described. At the initial stage of its development metacestode of S. furcata forms lacuna primitiva. The primordium of scolex invaginates early into the posterior part of the larva, and then the scolex develops in the cyst cavity. There is only an anterior obturator valve developing in the cyst. Posterior obturator valve is absent, that results in the cyst remaining unlocked and the cercomer does not separate from the cyst. There is no lacuna primitiva in the cercomer. The tegument of metacestode gets covered with a solid fibrous layer at the final stage of morphogenesis. It makes the cyst partly or completely pressed in the anterior part of the cercomer when it grows. The similarity between S. furcata cysticercoids and morphologically related cysticercoids Hymenolepididae has been analysed.